I've got 6 2TB G-Drives in a RAID 10 configuration hanging off of an older Mac Mini (on 10.9.2) via FireWire 800. This was created using Disk Utility and involves no separate RAID hardware or software. A couple of slices have begun acting up leading me to believe I am headed toward replacing one or more drives in the not too distant future. The trouble is I don't know which physical drive contains the errant slice. How does one identify which physical drive to unplug?

Thanks for posting. Unfortunately unless you set up a labeling system on the drives for physical and software besides hooking them up one at a time you won't know which is which. If you tried to use system report to look up the s/n of the drive it will tell you the s/n of the firewire controller chip which will not be listed on the drive.